Readme.md

基于Hashtable实现IDictionary<TKey, TValue>接口（部分成员即可）。

参考文档：

Hashtable: https://msdn.microsoft.com/en-us/library/system.collections.hashtable(v=vs.110).aspx

IDictionary<TKey, TValue>: https://msdn.microsoft.com/en-us/library/s4ys34ea(v=vs.110).aspx

Hashtable.cs

namespace HashTableDict
{
    using System.Collections;
    using System.Collections.Generic;

    public class Hashtable<TKey, TValue> : IDictionary<TKey, TValue>
        where TKey : class
        where TValue : class
    {
        private readonly Hashtable _ht = new Hashtable();

        // 实现以下接口。
        
        public int Count
        {
            get { throw new System.NotImplementedException(); }
        }

        public bool ContainsKey(TKey key)
        {
            throw new System.NotImplementedException();
        }

        public void Add(TKey key, TValue value)
        {
            throw new System.NotImplementedException();
        }

        public bool Remove(TKey key)
        {
            throw new System.NotImplementedException();
        }

        public bool TryGetValue(TKey key, out TValue value)
        {
            throw new System.NotImplementedException();
        }

        public TValue this[TKey key]
        {
            get { throw new System.NotImplementedException(); }
            set { throw new System.NotImplementedException(); }
        }

        public void Clear()
        {
            throw new System.NotImplementedException();
        }

        /* 以下接口无需实现 */

        public IEnumerator<KeyValuePair<TKey, TValue>> GetEnumerator()
        {
            throw new System.NotImplementedException();
        }

        IEnumerator IEnumerable.GetEnumerator()
        {
            return GetEnumerator();
        }

        public void Add(KeyValuePair<TKey, TValue> item)
        {
            throw new System.NotImplementedException();
        }

        public bool Contains(KeyValuePair<TKey, TValue> item)
        {
            throw new System.NotImplementedException();
        }

        public void CopyTo(KeyValuePair<TKey, TValue>[] array, int arrayIndex)
        {
            throw new System.NotImplementedException();
        }

        public bool Remove(KeyValuePair<TKey, TValue> item)
        {
            throw new System.NotImplementedException();
        }

        public bool IsReadOnly
        {
            get { throw new System.NotImplementedException(); }
        }
        
        public ICollection<TKey> Keys
        {
            get { throw new System.NotImplementedException(); }
        }

        public ICollection<TValue> Values
        {
            get { throw new System.NotImplementedException(); }
        }
    }
}

    // 实现以下接口。

    public int Count
    {
        get { return _ht.Count; }
    }

    public bool ContainsKey(TKey key)
    {
        return _ht.ContainsKey(key);
    }

    public void Add(TKey key, TValue value)
    {
        _ht.Add(key, value);
    }

    public bool Remove(TKey key)
    {
        if (key == null)
        {
            throw new ArgumentNullException();
        }
        if (_ht.ContainsKey(key))
        {
            _ht.Remove(key);
            return true;
        }
        return false;
    }

    public bool TryGetValue(TKey key, out TValue value)
    {
        try
        {
            if (_ht.ContainsKey(key))
            {
                value = (TValue)_ht[key];
                return true;
            }
        }
        catch (Exception e)
        {
            //do something here...
        }
        value = null;
        return false;
    }

    public TValue this[TKey key]
    {
        get { return (TValue)_ht[key]; }
        set { _ht[key] = value; }
    }

    public void Clear()
    {
        _ht.Clear();
    }